1. Field of the Invention
This invention relates to golf bag cart drive units, and more specifically to golf bag cart drive units which may be mounted on conventional golf bag carts.
2. Description of the Prior Art
Although golf is an extremely popular game, transporting one's bag about the course while playing is a burdensome chore. A typical golf bag often contains a full complement of woods and irons as well as putters, extra balls, and other items making the bag quite heavy. Although electrically powered vehicles for transporting both golfers and their bags about the course are available, these vehicles are generally quite expensive and beyond the means of the average golfer.
Alternatively, lightweight golf bag carts are widely used for caddying single golf bags. Such carts are popular, especially if collapsible, and consequently widely used. However, these carts can also be burdensome to pull or push about the golf course, particularly if the user has arthritis or some other ailment making muscular exertion painful or difficult.
A wide variety of powered golf bag carts have previously been developed. However, all of these power-assisted carts have significant drawbacks. Many single bag carts have been specially designed to include integral drive means which cannot be removed from the cart. This increases the cost of the entire assembly. Secondly, the drive unit cannot be transferred to other carts. Furthermore, these carts including integral drive means tend to be relatively complex.
A number of drive units claiming to be adapatable to any single bag cart have also previously been developed. One type of unit comprises an "add-on" power driven third wheel which either pulls or pushes the cart. Examples of this type of unit may be seen in U.S. Pat. Nos. 4,105,084 issued Aug. 8, 1978 to Baak, 3,941,198 issued Mar. 2, 1976 to Kappas, and 3,059,713 issued Oct. 23, 1962 to Beggs. These units are extremely bulky, cumbersome, and heavy. Further, although these units claim to be mountable on any two-wheel cart, such installation can be quite difficult, requiring severe physical modifications to the golf cart. Finally, because the units are generally located directly under the handle, they interfere with the user's feet as he attempts to walk and pull or push the cart.
Other drive units are mounted on the cart so as to drive an existing cart wheel by its hub. This construction requires a relatively high torque motor to drive the relatively large diameter cart wheels and also requires a larger and heavier battery source. Further, these units must typically be permanently affixed to the cart frame requiring permanent modification of the cart, which can weaken the structural members. Examples of hub drive units are found in U.S. Pat. Nos. 4,106,583 issued Aug. 15, 1978 to Nemeth and 3,753,473 issued Aug. 21, 1973 to Hollis.
Another prior golf cart drive unit includes a driving pinion which engages the outer surface of an existing golf cart wheel to drive the unit, for example as in U.S. Pat. No. 3,167,146 issued Jan. 26, 1965 to Rudolph. This drive unit may be mounted only on carts having a relativley long wheel axle extending from the driven wheel, which is not typical in today's units and is limited in older style golf carts. Further, the drive unit must be permanently mounted on the cart frame so that it is not readily transferrable to other carts. This permanent affixation also makes it impossible to readily move the drive unit to a position which will not interfere with the folding of the golf bag cart. Although a spring biases the pinion against the cart wheel, this force is principally tangential to the point of contact providing relatively little effective biasing force. Further, the pinion is constantly biased against the cart wheel, especially during storage, providing a severe flat spot in the wheel. In extreme cases, the pinion will actually penetrate the wheel, damaging the wheel beyond repair.
A problem common with all of the above carts and units is that each drive unit, which cannot be moved from its driving orientation without totally removing it from the cart, interferes with the collapsing or folding of the cart. Consequently, a cart with one of the prior units installed thereon cannot be collapsed without totally removing the unit. This makes use, transportation, and storage extremely cumbersome and difficult.